This invention relates to herbicidal compositions which are effective, economical and environmentally compatible. More particularly, an improved herbicidal composition has been obtained by combining a fatty acid-based active ingredient with a glyphosate-based active ingredient.
Herbicides are widely used to control the rate of growth or to cause mortality in unwanted or undesirable plant species. Among the most widely used herbicides are those which are petrochemical-based. Although quite effective, many petrochemical-based herbicides are considered to pose hazards to the environment, as well as to humans, animals and aquatic life.
Due to concerns for such hazards posed by petrochemical-based herbicides, several environmentally compatible herbicides have been developed. Fatty acid based compounds having between eight and eighteen carbon atoms serve as an example of one class of environmentally compatible herbicides. These compounds occur naturally in soil and decompose quite rapidly (i.e., within about 1–3 days) within soil. An exemplary fatty acid-based herbicidal compositions is commercially available from Safer, Inc. under the trademark SHARPSHOOTER. This herbicidal composition utilizes an active ingredient which is a mixture of partially saponified fatty acids. Other fatty acid-based herbicidal compositions are disclosed in U.S. patent application Ser. Nos. 421,146 and 421,376, both of which were filed on Oct. 13, 1989.
Such fatty acid-based herbicides are quite effective for most applications. However, like most pesticides, they are not well suited for all applications. For example, these compositions are not able to translocate and are thus only effective on the plant tissue which is contacted by the herbicidal composition. Also, because such compositions are used in relatively high concentrations of active ingredient, i.e., 3 to 6 percent, their use can be costly.
One petrochemical-based herbicide which apparently exhibits minimal environmental impact is a glyphosate-based composition. This compound is an effective, broad spectrum herbicide which has the ability to translocate within plant systems. Glyphosate-based herbicides can be expensive to use, and typically must be applied at concentrations in the range of 1 to 2 percent. One potential drawback to the use of glyphosate-based compounds is that they do not occur naturally and have an average half-life in soil slightly less than 60 days.
While fatty acid based herbicides are advantageous due to their environmental compatibility, they lack the ability to translocate, and must be used in relatively high concentrations. Glyphosate-based herbicides must also be used in relatively high concentrations and are relatively expensive. Moreover, it would be desirable to provide a herbicidal composition which combines the beneficial features of these herbicides, while reducing the amounts of non-naturally-occurring compounds, such as glyphosate, which are environmentally released.
It is thus an object of the invention to provide an effective, broad spectrum herbicide which is environmentally compatible and economically feasible. Another object is to provide a herbicide which has the advantages of the fatty acid-based herbicide, but which also has the ability to translocate. An additional object of the invention is to provide an effective herbicidal composition with improved efficacy. A further object of the invention is to provide a herbicidal composition which combines two known active ingredients in such a way that the concentration of each of the individual components is present at levels less than what is recommended for herbicidal activity. It is also an object of the invention to provide an effective herbicide while at the same time reducing the pesticide load in the environment. Other objects will be apparent to those skilled in the art upon reading the following disclosure.